The offspring of which individuals would be least closely related? 3 and 7 11 and 14 17 and 18 16 and 19

Aresearcher is studying the science of attractiveness and asks volunteer test subjects to rank what trait they find most attractive in a person what type of variable is the dependent variable in this experiment

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

The “ecological footprint” left by a citizen of a developed nation is about four times larger than that left by a citizen of a developing nation. why is this the case?